Synthesis and reactions of derivatives of 5-alkyl- and 5-halo-pyrimidines (original) (raw)

Chemical syntheses of 1-(2-O-acetyl-5-azido-5-deoxy-3-O-p-toluenesulfonyl-[3-D-xylofuranosyl)-5-iodo- ,-5-fluoro-, and-5-trifluoromethyl-uracil nucleosides (11-13) as well as the thymine analogue 10 were performed from a sugar precursor and the corresponding uracil bases. Partial deblocking of 10-13 gave the 5'-azido-5'-deoxynucleosides 14-17. The 3',5'-diazido-3',5'-dideoxyribonucleosides were obtained in the same way. The 2',3'-anhydro analogue 20 was prepared by treatment of 10 with potassium carbonate in methanol or a basic ion-exchange resin. Reaction of 10 with azide or methanethiolate ions gave 2'-azido-and 2'-thiomethyl-ribonucleosides, respectively. Similarly, 13 gave a 2'-thiomethylribonucleoside on treatment with methanethiolate ion. Treatment of 16 with phenoxythiocarbonyl chloride in basic medium afforded a 2',3'-anhydro derivative and not the expected ester.